【摘要】 对比研究硼砂细化变质剂(Na2B4O7)、晶粒细化剂(Al-5%Ti)+钠盐变质剂(NaF(2/3)+NaCl(1/3))混合剂和高密度脉冲电流的复合作用对ZL102铝硅合金铸件凝固组织的影响,并测试了4种工艺条件下浇注拉伸试样的力学性能。这4种工艺条件分别为:在合金液熔炼过程中,除了加脱氧剂外不做任何处理;凝固过程中单独施加高密度电脉冲;添加晶粒细化剂和钠盐变质剂混合剂,或者添加硼砂变质细化剂,并施加高密度电脉冲。研究结果表明:脉冲电流对铝硅合金中的α相细化效果显著,对共晶硅起到一定的变质作用;无水硼砂细化变质剂与脉冲电流的复合变质处理,对共晶硅片具有粗化作用;晶粒细化剂、钠盐变质剂混合剂与脉冲电流的复合作用使α相枝晶长度及其枝晶间距减小,共晶硅片细密,与原始试件相比较伸长率提高了77.1%,抗拉强度提高了36.7%。更多还原

【Abstract】 The effect of borax refinement modifier(Na2B4O7),mixture of grain refiner(Al-5%Ti) and sodium modifier(NaF(2/3)+NaCl(1/3)),pulse electric current on the solidified microstructure of Al-11.6wt%Si alloy was contrastively investigated,and the mechanical properties of specimens prepared at the four casting conditions were measured respectively.The four conditions are as follows: the molten alloy only with the addition of deoxidant during melting;only applying high-density pulse electric current on castings during solidification;compound addition of grain refiner and sodium modifier,and addition of borax r modifier liquid along with applying pulse electric current during melting.The experimental results show that pulse electric current have a remarkable refining effect on α-dendrite and have a certain modification effect on eutectic silicon flake;the compound-modification of anhydrous-borax and pulse electric current coarsen eutectic silicon flake;the compound addition grain refiner and sodium modifier along with pulse current can refine the dendritic structure of α-Al and decrease the dendritic arm spacing.The elongation and tensile strength increase by 77.1% and 36.7% respectively in comparison with original specimen.更多还原